1. Technical Field
This is related to systems for optically monitoring objects suspended in flowing fluid, and more particularly, to particle monitoring systems for monitoring the presence and size of debris in hydraulic fluid or in lubricants such as oil.
2. Related Technology
U.S. Pat. No. 5,572,320 to Reintjes et al. and U.S. Pat. No. 6,049,381 disclose in-situ fluid samplers for identifying particles in a flowing fluid with an optical near-field imaging device. U.S. Pat. No. 6,049,381 to Reintjes et al. discloses a real time suspended particle monitor that uses a pulsed collimated optical source to produce a series of images of particles in a flowing fluid. U.S. Pat. No. 7,921,739 to Fjerdingstad et al. discloses a real-time optical monitoring system having an automatic on line bottle sampling operation.
U.S. Pat. No. 8,056,400 to Reintjes et al. discloses a system for particle entrained fluid sampling in a high pressure or high flow rate fluid flow system.
U.S. Pat. No. 8,582,100 to Tucker et al. and U.S. Pat. No. 8,654,329 to Tucker et al. discloses systems with series and parallel optical particle sensors for optically monitoring debris and other particles in flowing fluid systems.